1. Field of the Invention
The present invention generally concerns traffic management. More specifically, the present invention concerns estimating time travel distributions on signalized arterials and thoroughfares.
2. Description of the Related Art
Systems for estimating traffic conditions have historically focused on highways. Highways carry a majority of all vehicle-miles traveled on roads and are instrumented with traffic detectors. Notably, highways lack traffic signals (i.e., they are not “signalized”). Estimating traffic conditions on signalized streets represents a far greater challenge for two main reasons. First, traffic flows are interrupted because vehicles must stop at signalized intersections. These interruptions generate complex traffic patterns. Second, instrumentation amongst signalized arterials is sparse because the low traffic volumes make such instrumentation difficult to justify economically.
In recent years, however, global positioning system (GPS) connected devices have become a viable alternative to traditional traffic detectors for collecting data. As a result of the permeation of GPS connected devices, travel information services now commonly offer information related to arterial conditions. Although such information is frequently available, the actual quality of the traffic estimations provided remains dubious.
Even the most cursory of comparisons between information from multiple service providers reveals glaring differences in approximated signalized arterial traffic conditions. The low quality of such estimations is usually a result of having been produced from a limited set of observations. Recent efforts, however, have sought to increase data collection by using re-identification technologies.
Such techniques have been based on be based on magnetic signatures, toll tags, license plates, or embedded devices. The sampling sizes obtained from such technologies are orders of magnitude greater than those obtained from mobile GPS units. Sensys Networks, Inc. of Berkeley, Calif., for example, collects arterial travel time data using magnetic re-identification and yields sampling rates of up to 50%. Notwithstanding these recently improved observation techniques, there remains a need to provide more accurate estimates of traffic conditions on signalized arterials.